The present invention relates generally to set screws for use with spinal implant systems to attach an elongate support member to bone, and more particularly relates to a set screw having a friction member positioned at a distal end of the set screw which frictionally engages an elongate support member positioned within a connector device to prevent movement of the elongate support member relative to the connector device.
Several techniques and systems have been developed for fixing and/or stabilizing the spinal column. In one type of system, a connecting element such as an elongate spinal rod is disposed longitudinally along a length of the spinal column or along several vertebrae of the spinal column. The spinal rod is attached to various vertebrae by way of a number of bone anchors. A variety of bone anchors can be used to attach the spinal rod to the vertebrae. For example, a bone screw can be threaded into one or more aspects of a vertebra such as, for example, the pedicle region of a vertebra. Additionally, a hook can be wrapped about a portion of a vertebra such as, for example, the lamina region of a vertebra. The bone anchor typically includes a connector portion including a passage or channel sized to receive the spinal rod, and a threaded opening in communication with the passage for receipt of a set screw. The set screw is threaded through the opening and into abutment against the spinal rod to capture the spinal rod within the passage. However, the force applied to the spinal rod by the set screw is sometimes insufficient to prevent rotational or translational movement of the spinal rod relative to the connector portion of the bone anchor, and may also exert excessive force or stress onto the connector member or the spinal rod and/or penetrate or cut into the spinal rod, thereby weakening or negatively affecting the structural integrity of the spinal rod and/or the connector member.
Thus, there remains a need for an improved set screw for use with a spinal implant system. The present invention satisfies this need and provides other benefits and advantages in a novel and unobvious manner.